Microelectronic devices, such as semiconductor devices and field emission displays, are generally fabricated on and/or in microelectronic workpieces using several different types of machines (“tools”). Many such processing machines have a single processing station that performs one or more procedures on the workpieces. Other processing machines have a plurality of processing stations that perform a series of different procedures on individual workpieces or batches of workpieces. In a typical fabrication process, one or more layers of conductive materials are formed on the workpieces during deposition stages. The workpieces are then typically subject to etching and/or polishing procedures (i.e., planarization) to remove a portion of the deposited conductive layers for forming electrically isolated contacts and/or conductive lines.
Plating tools that plate metals or other materials on the workpieces are becoming an increasingly useful type of processing machine. Electroplating and electroless plating techniques can be used to deposit nickel, copper, solder, permalloy, gold, silver, platinum and other metals onto workpieces for forming blanket layers or patterned layers. A typical metal plating process involves depositing a seed layer onto the surface of the workpiece using chemical vapor deposition (CVD), physical vapor deposition (PVD), or other suitable methods. After forming the seed layer, a blanket layer or pattern layer of metal may be deposited on the workpiece by an appropriate electroplating or electroless processing technique. In either process, the workpiece may then be cleaned, etched and/or annealed in subsequent procedures before transferring the workpiece to another processing machine.
In some conventional electroless processing techniques, the fluid used to plate conductive material onto the microelectronic workpiece is heated. For example, cobalt, nickel, and their alloys with tungsten are typically plated onto a microelectronic workpiece using a heated electroless solution. One drawback with heating the electroless solution is that it can be difficult to adequately control the processing temperature and flow uniformity at the interface between the microelectronic workpiece and the electroless processing liquid. This can adversely affect the chemical plating reaction occurring at the surface of the microelectronic workpiece and the uniformity with which multiple microelectronic workpieces are processed.